alternate

do something in turns

We take turns on the night shift

go back and forth; swing back and forth between two states or conditions

reverse (a direction, attitude, or course of action)

be an understudy or alternate for a role

exchange people temporarily to fulfill certain jobs and functions

occurring by turns; first one and then the other

alternating feelings of love and hate

every second one of a series

the cleaning lady comes on alternate Wednesdays

jam every other day"- the White Queen

of leaves and branches etc; first on one side and then on the other in two ranks along an axis; not paired

stems with alternate leaves

serving or used in place of another

an alternative plan

someone who takes the place of another person